1. Field of the Invention
This invention relates to a process for producing 4-carboxamido-5-cyano-2-imidazolone represented by the formula ##STR1## More particularly, this invention relates to an improved process for producing 4-carboxamido-5-cyano-2-imidazolone which comprises reacting diaminomaleonitrile (hereinafter referred to as DAMN) with carbon dioxide in a polar solvent, optionally in the presence of a basic catalyst.
2. Description of the Prior Art
4-Carboxamido-5-cyano-2-imidazolone obtained by the process of this invention has been known to be useful as a plant browth regulating agent, for example, for reducing the germination time of pea seeds and as an intermediate for the preparation of various pharmaceutical and agricultural agents, for example, uric acid, as described in R. A. Sanchez et al., U.S. Pat. No. 3,868,386. Further, 4-carboxamido-5-cyano-2-imidazolone can be converted into resins which are useful as textile crease and shrink-proofing agents, as described in U.S. Pat. No. 3,868,386.
Hitherto, a process for producing 4-carboxamido-5-cyano-2-imidazolone comprising a reaction between DAMN and a water-soluble bicarbonate salt such as ammonium bicarbonate, potassium bicarbonate, sodium bicarbonate, etc., in aqueous alkaline media has been disclosed in, for example, U.S. Pat. No. 3,868,386. However, the above conventional process is not considered to be an advantageous process, in particular, from the industrial standpoint, since the solvent used in the process is limited to only water. That is, a polar solvent solution of DAMN obtainable from a manufacturing step of DAMN cannot be used directly in the process for producing 4-carboxamido-5-cyano-2-imidazolone taught in the above prior art, and in addition, the use of an aqueous solution of DAMN is not advantageous due to the fact that the solubility of DAMN in water is low (about 0.6% at room temperature) and that the aqueous solution of DAMN tends to form a tar-like polymer due to the polymerization of HCN during the storage of the solution for a prolonged period of time.